Drop hammer



May 22, 1928. 1,670,493

R. s. CLARK ET AL I DROP HAMMER Filed Dec. 20, 192], 4 Sheets-Sheet l Q1402 ml 01 I. 61mm May 22, 1928.

R. S. CLARK El" AL DROP HAMMER Filed Dec. 20, 1921 4 Sheets-Sheet 2 M 6m: nu;

May 22,1928.

2 1,670,493 R. s. CLARK ET AL DROP HAMMER Filed Dec. 20, 1921 4 Sheet et 3 I III II ill 7/14 71/12 /I/I II III I! II cerrfer f Gudgeo g III/Ill];

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4 Sheets-Sheet, 4

May 22, 1928.

R. S. CLARK ET AL DROP HAMMER Filed Dec. 20, 1921 FFHC RAYMOND S. CLARK, GEORGE C. PRIME, AND MORTON C. TALCOTT, OF HARTFORD, CON- NECTICU T, ASSIGNOBS TO THE BILLINGS & SPENCER COMPANY, OF HARTFORD, CON- NECTICUT, A CORPORATION OF CONNECTICUT.

DROP HAMMER.

Application filed December 20, 1921. Serial No. 523,606.

This invention relates to drop hammers and has as its object to provide a machine of this character with various features of novelty and advantage, and more particularly to improve the construction so that the board, by -means of which the hammer is raised, is given a longer life and is lifted and clamped in a more effective manner.

In the accompanying drawings:

Fig. 1 is a front elevation of the entire machine;

Fig. 1 is a side elevation showing the connection between the foot treadle and the pull rod for the board clamps;

Fig. 2 is a side view of the machine in vertical section; l

Fig.3 is a top plan view of the head frame which carries the lifting rolls for the board;

Fig. clamp 4 is a top plan view of the board frame and the clamps carried there- Fig. 5 is a horizontal view taken substantially on line 55 of Fig. 1; u

Fig. 6 is a horizontal view in section taken along line 66 of Fig. 1.

Figs. 7 and 8 are details. Referring to the drawin s in detail, (1 denotes the base of the mac ine; b, b, the uprights adjustably mounted thereon, as

hereinafter described; 0, the head frame mounted on the to s of the standards b and carrying the ammer raising mechanism; and d, the frame in which the board clam s are mounted. The standards b are provided with op osing guide-wa s e. for

the hammer f to w ich s secured t e board This board 9, together with the hammer carried thereby, is raised by means of the hammer raising mechanism including the rolls )5. mounted, as stated, in the head frame, and the board is held in its raised position by the shoes or clamps z. The movement of the rolls into and out of ippin'g relationto the board is controlled t rough the friction bar In by the movement of the hammer. The clam s i are controlled by means of a foot trea le Z.

Referring now more particularly to the 5 construction of the machine, it-will e noted,

particularly from Fig. 5, that the. gu deways e are removably secured 1n vertical grooves in the opposin faces of the standards I; by means of bo ts 26,'the inner when the ways become worn they may be removed from the uprights and their active faces refinished or new ways may be substituted in their place.

In machines of this type, the lives of the boards are usually very ,short owing to the fact that they splinter and split under the strains-"and jars to which they are subjected when the hammer is dropped onto the lower die, and also to the crushing strains to which the board is subjected by the lifting rolls and the board clamps. Frequent renewal Y of these boards is an item of considerable expense, for the boards themselves must be of the best material and therefore costly, and the machine must stand idle during its repair. One of the main objects of the present invention is to provide improvements which result in prolongation of the lives of the boards and to this end the hammer raising mechanism is such that the crushing strains exerted thereby against the board are greatly reduced and heavier hammers can thereby be employed.

In accordance with the resent invention, the hammer raising mec anism comprises two sets of rolls, ,one set arranged above the other, and means for causing the rolls of the. two sets to grip the board "with substantiall like force. In the present illustrative isclosure of the invention, each of the rolls h is keyed to a respective shaft 35, and these shafts are journaled in eccentrics 36 mounted for rotation in bearings 37- provided in the 'upri ht standards 38 of the head frame 0. T e shafts 35'of the respective sets are connected by gears 39 and are constantly driven by belts passing about the pulleys 40. The eccentrics 36 for each shaft 35 are connected by yokes 42. If desired, one roll of each set, for'instance the rear roll, ma be fixed against movement to and from t e board, while the front rolls are arranged for lateral movement, but preferably the arrangement is such that the rolls of each set move in unison towards and away from each other to grip the board and stance, corresponding end armsof the yokes for the respective sets of rolls are, provided with intermeshing segment gears 43. I The corresponding yokes of the two sets of rolls,

kyokes,

that

in the present instance the forward are so connected to the friction bar when this bar is, dropped the two sets of rolls will exert alike amount of pressure in gripping the hammer board. In the present instance, the friction bar 70 is fixed at its upper end as at 45 to the forward yoke 42. of the lower set of rolls. Connectedto this yoke and having sliding movement in an opening through a pin 46 carried by the forward yoke of the upper set of .rolls is a rod 47. Between the upper and lower yokes and bearing against the pin 46 is a s ring pin 48. About the upper end of the rod 4 and bearing a ainst the pin 46 is a spring 49,.the tension 0% which may be adjusted by nuts 50. The rod 47 constitutes a link having a loose motion connection with one of the okes, and the extent of this lost motion'is spring 49 is so adjusted that when the. friction bar is dropped, the-rolls of the upper set will be moved with substantially the same force against the board as the rolls of the lower set.

When the friction bar is raised, the action of spring 48 is to withdraw the upper roll from the board thereby insuring that both rolls withdraw substantially together so that the board does not drag on either roll. Suchdragging may have the effect of polishing a spot on the board, or else of unduly wearing away the surface'and in either case interferes with the lifting action of the rolls by the local change in the friction. coefficient.

The dropping of the friction bar k,which results in moving the lifting rolls into gripen gagement with the board, is contro ed by the movement of the hammer on its downward stroke through the knock-off mechanism which is most clearl shown in Fig. 5. The lower end of the riction bar the piston 78 1s-an 011 port 85. It will be has a sliding movement in a vertical opening through a boss on one of the standards 6 and is provided with .a shoulder 56 which is adapted to rest, when the bar is in raised position, on the endof a stop pin 57 slida- ,bly'mounted in a bore 58 at right angles to the-friction bar. This stop pin is adjustably connected by an arm, 59 to a knockoff plug 60 mounted for sliding movement in a bore 61 in the standard b. The stop pin' 57 is normall urgedto'wards the friction bar Is and t e knock-off plug is normally urged to a position where the projecting-end thereof extends into the path of movement of the falling hammer by means of a spring 62 housed Within the knock-off plug. The rojecting end of the knock-off plug is beveled as shown in Fig. 1, and the lmited' by the springs described. The

against theprojecting'end of the knock-oil plug and forces this mer is dropped. 4

To accomplish this raising of the friction rod or bar, a sleeve 7 Q is adjustably connected to it and pivotally carries a resilient arm 71 in the form of a laminate leaf spring the inner end of which is'struck by a stud 72 plug in when thehamwhen the hammer is raised. The outer endof the spring .71 is connected'by a link 7 3 to a vertically adjustable bracket 74. It is of advantage to have the arm 71 resilient and more particularly in the form of a leaf spring, as shown, forthis arm will then take up the shocks and jars to which it is sub-- jected when the stud 72 hits it and breakage of the parts is obviated. At the same time,

the leaf spring possesses considerable strength and is of suflicient rigidity to insure ereupon- 'the rolls withdraw, the

hammer falls and the cycle is repeated. This sustained reciprocation-continues for as long as tlla board clamp is held open by the foot trea e.

' Referring to Figure 2 it will be seen that the body ortion of the hammer is provided with a cylinder 77 in which works a piston 78 connected to a hollow stem 79 which, in turn, is connected to the board 9 as hereinafter described. Leading through the side of the cylinder 77 is a port 80. f The space in the chamber of the cylinder 77 above the piston 78 communicates with the atmosphere through a groove 81 pipe 82, a port 83 in the piston and a ball valve 84. Leading from the hollow stem to the periphery of seen that with the arrangement described,

die, the piston 78 which is connected to the board g, owing to its inertia, willmove downwardly in the cylinder 77 and compress the air in the lower part of this chamber. This' air forms a cushion. As the piston thus moves downwardly relative to the cylinder 77, the air ,will flow past the valve 84'and revent a vacuum. which would otherwise ex1stin-the space above the piston 78. The piston, when the hammer strikes the lower die, will move tothe approximate position shown by dotted lines in Fig. 2, and in this position alr will flow throu h the port 80 to the space above the iston. The piston, when it compresses the a r in the lower part acrea e of the cylinder, will tend to rebound but it is prevented from so doing with any jar or shock by the air entrapped above the piston,

this air being prevented from flowing past the ball valve as this valve closes with the pressure. .When the board is raised, the hammer, owing. to its weight, will lag behind the iston so that by the time thehammer reac es' its u permost position, the piston 78 is above t e port 80 permitting air to again flow into the lower part of the cylinin a very economical yet effective manner as follows. Integral with the stem 79 is an attac'hingplate 87 having a horizontally extending rib 88 forming the groove 81 between this rib and the top-of the stem 79. The ends of the plate 87 have vertical side flanges 89 which engage the edge of the board and thus prevent the board from moving in the direction of its width. 90 is a securing plate havin a flange 91 at its lower edge adapted to fit 1n the groove 81. The board is positioned between the plates 87 and 90 and is secured in place by bolts 92 passing through the.plates and the board. It will be seen that with this arrangement, the securing plate is interlocked so to speak by the interengaging. r'bs 88 and 91 against vertical movement relative to the attaching plate87.

Each of the bolts 92 is anchored or supported at each side'of the board by the plates 87 and 90.

Reference will now be made to the clamping mechanism for holding the board and hammer in raised-position, this mechanism being most clearly shown in Figs. 2 and 4.

In the present illustrative disclosure, the board clamps 21 of this mechanism are independently adjustable but are operable in unison. Passing through the hubs 95 of each clam is a pin 96 97 eccentrically journaled in eccentric bushings 98 mounted for turning movement in bearings 99 in the upstanding flanges 100 of the frame d. The eccentric bushings 98 for each shaft are connected by yokes 101, these yokes including connecting bolts 102. The connecting bolt 102 .is received by an elongated slot 103 in the head of a screw 104 adjustably secured to the frame d in any suitable manner as by nuts 105. In will be seen that by longitudinally adjusting the respective screws 104, the eccentric bushings 98 will be turned and,thus vary the position of the clamping members. .The clamping members are moved into and out of engagement with the board so as to grip having eccentric ends the same and hold it in raised position and to release it so that the hammer may drop, by turning the eccentric pins 96. In the present instance, these pins are connected by a link 107 so that the pins will rotate in unison and thus simultaneously move the clamping members into clam ing engagement with the board or out o engagement therewith, depending on the directlon in which the pins are rotated. The pins 96 are rotatedin'a direction to withdraw the clamps i from the board by depressing the foot treadle 1, this treadle being operativel connected, as shown in Fig. 1*, to the pul rod'110 which, in turn, is connected at its upper end to an arm 111 extending from a sleeve 112 keyed to the end of one of the pins 96. When the foot of-the operator is removed from the treadle l, the pull rod of its own weight will fall, andthe eccentric pins will be turned in a direction to move the clamping members into engagement with the board so as to hold the same in raised position. In such movement the proximate ends of the clamps slide on the upper face of the board-clamp frame d.

The uprights or standards b, togetherwith the mechanism carried thereby, areadapted to be ad'usted transversely of the base a of the mac ine by wedges 125 which are most clearly shown in Fig. 6. It will be seen that the to of the base of the machine is transverse y grooved as at 126 and the uprights b have a depending web or tongue 127 closely fittin in these grooves. The web or tongue 127 0 each standard has an o 'ening 128 therethrough, the'inner edge of w ich is inclined, as shown. The top of the base a is also provided with grooves 129 at right angles to the grooves 126 and in these grooves 129 the wedges 125 are positioned. Each of these wedges has on its inner. edge a'cam surface 130 inclined simi- .the uprights, for instance to the left referrmg to Fig. 6,-the forward bolt of the right hand wedge and the rear bolt of the le t hand wedge will. be loosened and the other two bolts will be tightened up, and then after the standards have been adjusted,

the forward and rear bolts for the right.

and left handwedges, respectively, will be tightened to hold the wedges in adjusted position. The uprights are further clamped in adjusted position by bolts 133.

In order to adjust the lower die and securely hold it in adjusted position; relative 1-to the upper die carried by the hammer, a'

clamping or vise arrangement, shown most clearly 1n'Figs. 1. and 6, is provided. 135 designates a shoe adapted to fit'in an undercut groove 136 in the anvil portion of the base a. 137 is a lower die. having a dovetail tongue 138 fitting in a dove-tail groove 139 in the top of the shoe.-

- As shown in Fig. v6, extendingacross the be seen that with the-arrangementdescribed,

after the shoe, together with the die thereon, is positionedon the base, the bars 140; 141, are put in place and secured together by the tie bolts 142; then, by turning up the screws 143, the die 137 will be adjusted and held in proper position relative to the upper die carried by the hammer.

The above described relative movement,"

permitted between the upper and lower rolls provides compensation for a condition in the oard which is brought about by the action thereon of the rolls themselves. It will be noted that only the central part of the length ofthe board is subject to the rolling or squeezing action of both pairs of rolls and that short parts of the board at each end of such central part are subject to the rolling action of only one pair of rolls. This inequality of rolling effect on the board is manifested more especially under sustained all) rapid reciprocation of the hammer when the differently rolled parts have not a sufficient recovery interval between strokes, and results in slippage of one or both pairs of rolls with consequent misbehavior of the hammer and wear on the board. Correction of the difficulty in the obvious way, as b increasing the gripping pressure, is possib e, but not satisfactory, because increased pressure beyond a certain point reat-ly shortens the useful life of the boar but by giving the upper and lower rolls an opportunity for slight relative movement with respect to each other and while engaged with the board the difiiculty referred to is avoided without applying excessive pressure, and thereby sustained reciprocation is rendered possible with hammers 'of -much greater weight than heretofore used in board drop hammers. It will be seen therefore that the principle of this invention contemplates broadly the provision of relative motion between ono of the rolls of each of the sets of boardifting rolls whether provided by the particular spring arrangement shown in the drawing or equivalent mechanism having the same purpose and tending to compensate the conditions referred to.

As a'means of keeping the friction surface of the board uniform from end to end, that is to say, with substantially the same friction coeflicient at all points, this invention provides for the locationof the board clamp below the lowermost pairaof rolls, where it gagement with the board surface, the res-- sure being produced by the weight 0 the friction bar and its connections,.as above pointed out, and transmitted substantially equally to the upper and lower rolls.

What we claim is 1. In a dro -hammer, a frame, a hammer suitably gui' ed therein for reciprocating vertical motion, a board secured to said hammer, apluralit of lifting rolls spaced apart longitudinal y of said board, and

means for bringing said rolls into gripping engagement \Vltll said board, saldmeans includlng a compensatin connection between said rolls permitting t em to accommodate themselves to grip said board. I

2. A board drop-hammer comprising the combination with the hammer and hammer board,of a plurality of pairs of driven lifting rolls for the latter, pressure-applying mechanism for said rolls automatically controlled by the hammer to produce sustained hammer reciprocation, .andmeans for permitting relative compensating movement between a roll of one of said pairs and a roll of another'of said pairs.

3. -A board drop-hammer comprising, in combination with the hammer and hammer board, a lurality of pairs of driven lifting rolls fort e latter, pressure-applying mechanism for said rolls automatically controlled by the hammer, means for permitting'relative compensating movement between a roll of one pair and a roll of another pair, and a board clamp placed below said rolls.

4. A board drop-hammer including a board-supported hammer, a plurality of pairs of driven lifting rolls, pressure-applying mechanism connected with a roll of each pair for Ipressing them against the board, means w ereby the reciprocation of the hammer automatically actuates and releases said mechanism to produce sustained hammer reciprocation and means included in board-supported hammer,

said pressure-applying mechanism for permitting relative movement between said rolls. f I

5. A board drop-hammer including a board-supported hammer, a plurality of pairs of driven lifting rolls, pressure-apply ing mechanism connected with a roll of each pair and adapted for and withdrawing them from the board, means included in said mechanism for permitting relative movement between said rolls, and hammer-operated means for controlling said mechanism to produce sustained hammer reciprocation.

6. A board drophammer including a.

board-supported hammer, a plurality of pairs of driven lifting rolls, a friction-bar connected to impart its weight to one roll of each of said pairs, for pressing them against the board, means in said connection permitting relative movement between. said rolls and means on the hammer for autogiatically raising and releasing said friction ar.

7 ..A board drop-hammer including a a plurality of pairs of driven lifting rolls, hammer-controlled mechanism connected with a roll of each pair' for pressing them against and withdrawing thein from the board, and a spring associated with one of the rolls permitting compensating movement thereof relativeto the other.

8. A board drop-hammer including a board-supported hammer, a plurality of pairs of driven lifting rolls, pressure-applying mechanism connected with a roll of each pair for pressing them against "the board, the connection with one of said rolls being yielding and means whereby the reciprocation of the hammer controls said mechanism to produce sustained hammer reciprocation.

9. A board-supported pairs of driven connected to, and permitting relative movement between, one roll of each pair, means whereby the hammer releases and raises p said friction bar to move sa1d rolls toward and from the board and means insuring conoint withdrawal of both said rolls from the oard.

10. A board drop-hammer including a' a plurality of board-supported hammer, pairs of driven lifting rolls, pressure-applying mechanism connected to one roll 0 each pairfor pressing them against the board and permitting relative movement between them, a spring (48) adapted to act on one of the rolls to withdraw it from the board, and means for controlling said pressure-applying mechanism to produce sustained hammer reciprocation.

11. A board drop-hammer including a moving them toward .mer is secured,

mer suitably guided Y ing vertical motion,

board drop-hammer including ahammer, a plurality of lifting rolls, a friction-bar pairs of driven lifting rolls, mechanism adapted for applying substantially the same amount of pressure to one roll of each of said pairs and permitting relativemovement between said rolls, the reciprocating hammer for automatically causing said mechanism to move said rolls toward and'from the board. 7

12. A board drop-hammer including a board-supported hammer, in combination withthe hammer and hammer-board, a plurality of pairs of driven lifting rolls for the latter, one of the rolls of each pair being journalled in an eccentric support, an arm on each of said eccentric supports, mechanismfor applying pressure to said arms includin means for permitting relative movement t erebetween, and means whereby the hammer controls said mechanism.

13. In a drop-hammer, a frame, a hammer suit-ably guided therein for reciprocating vertical motion, a board to which said hamtwo pairs of lifting rolls arranged one above the other, eccentrics in which said rolls are journalled, and means for turning said eccentrics to move. said rolls into and out. of gripping relation to said board and including an equalizing connection between the eccentrics of the two airs of rolls whereby board with substantially like force.

' 14.-In a drop-hammer, a frame, a hamtherein for reciprocata board to which said hammer is secured, two pairs of lifting rolls arranged one above the other, eccentrics in which said rollsare journalled, a yoke connecting the eccentrics for each roll, a friction bar connected to one of said yokes, a rod connectedto said last mentioned yoke and having sliding relation to the yoke connected to the eccentrics for a roll of the other air, 'and oppositely acting springs carrie by said rod and bearing against sa1d last mentioned yoke.

15. In a drop-hammer, for reciprocating vertical motion, a secur ng late connected thereto, an attachin plate, interlocking portions on said plates or preventing relative vertical movement therebetween, a board interposed between said plates, and means for holding said plates against said board.

16. In a drop-hammer, for reciprocating vertical motion, a securing plate connected to said hammer and having a horizontally extending groove, an attachi-ng' plate having a ortion closely fitting in said groove, a boar ,the lower end of which is interposed between said plates, and tie bolts, assin through said plates and board.

17. n a rop-hammer, a hammer guided for reciprocating vertical motion, a securing and means associated with v the same grip the a hammer guided a hammer guided a rib forming a groove therebeneath, a securing plate having at its lower edge a flange spring lever carried on said friction bar and a member on the hammer adapted to engage said spring lever to move the bar and release the hammer.

19. In a drop-hammer, a frame, a hammer guided therein for reciprocating vertical motion and having a stud, lifting means for said hammer, a friction bar associated with said lifting means, a sleeve on said friction bar, a leaf spring carried by said sleeve, and a link between one end of said leaf spring and frame, the other end of said leaf spring being in the pathpf travel of said stud.

20. In a drop-hammer, a frame including a base a pair of uprights thereon, a hammer guide in said uprights for, reciprocating vertical motion, and means for adjusting said uprights laterally of said base and including a pair of o positely acting wedges positioned in said base and engaging the respective uprights and screws one ateach on of each wedge and within the base for adjusting the same.

' uprights 21. In a drop-hammer, a base, a pair of uprights arising therefrom, a hammer guided in said u rights'for reciprocating motion, a pair. 0 wedges carried by said base and having their opposed edges similarly inclined to form cam surfaces, said cam surfaces en aging against the respective uprights, an means at each end of each wedge and within the base for longitudinally adjusting saidwedge and holding it in adjusted position. T e 22. In a drop-hammer, a base, a pair of arising therefrom, a hammer guided for reciprocatinglvertical motion in said uprights, said base aving beneath each upright a transverse groove and a longitudinally extending groove intersecting said transverse groove, said uprights having tongues fitting in said transverse grooves and openings throughsaid tongues with their inner edges longitudinally inclined in similar directions, a wedge fitting in each longitudinally extending groove and having a cam surface engaging the inner edge of the respective openings in said tongues, and

screws one in threaded engagement with each end of each wedge within said longitudinal grooves and anchored against, longitudinal movement relative to said base.

RAYMOND s. CLARK.

GEORGE o. PRIME. MoRTon o. TALCOTT. 

